Fluctuation of Plasmonically Induced Transparency Peaks within Multi-Rectangle Resonators

Numerical investigations were conducted of the plasmonically induced transparency (PIT) effect observed in a metal-insulator-metal waveguide coupled to asymmetric three-rectangle resonators, wherein, of the two PIT peaks that were generated, one PIT peak fell while the other PIT peak rose. PIT has been widely studied due to its sensing, slow light, and nonlinear effects, and it has a high potential for use in optical communication systems. To gain a better understanding of the PIT effect in multi-rectangle resonators, its corresponding properties, effects, and performance were numerically investigated based on PIT peak fluctuations. By modifying geometric parameters and filling dielectrics, we not only realized the off-to-on PIT optical response within single or double peaks but also obtained the peak fluctuation. Furthermore, our findings were found to be consistent with those of finite element simulations. These proposed structures have wide potential for use in sensing applications.